Increased calcium intake has proven effective in increasing bone mineral density in children, but the effect disappears when calcium supplements are discontinued. Increased dietary calcium from daily and other food sources may have an even greater impact on bone density than that achieved by calcium supplements, but achieving sustained increased calcium from food sources has not been demonstrated. In addition, the effects of baseline characteristics of calcium intake and bone density and puberty status may influence the response to intervention. This study will develop and implement a Behavioral Modification-Nutrition Education (BM-NE) Intervention Program aimed at increasing dietary calcium Male and female subjects (n=154), ages 7-10 years (Tanner stage I or II), will be randomly assigned to participate in an intensive BM-NE intervention group to increase intake to 1500 mg/d or a group that will receive usual care (UC) as counseling on bone health. The BM-NE Program will consist of five separate group sessions for parents and children over a five to six week period, and use individualized plans to increase calcium intake. Participants will be recruited into two groups: a group of healthy children (i.e.,no known chronic disease or previous oral steroid exposure) with no known risk factors, and a group of healthy children with potential risk factors for low bone density (previous fracture from usual childhood activities, daily refusal, or lactose intolerance, family history of osteoporosis). These two groups will be equally represented in their assignment to BM-NE and UC groups. This latter strategy will be used to determine whether the presence of risk factors influences participant compliance with the programs. We hypothesize that (a) at the end of 36 months the BM-NE group will have increased dietary calcium of at least 300 mg/d in the no-risk BM-NE group compared to those receiving UC, (b) baseline calcium intake and presence of risk factors will be associated with changes in calcium intake over the course of the study, and (c) after controlling for important co-variates such as increases in body size and sexual and skeletal maturation, changes in BMD will be associated with calcium intake and physical activity. These findings will help define important behavioral strategies for increasing peak bone mass and prevention of osteoporosis later in life that can be implemented in a short period of time with long-lasting effects. Furthermore, it will help quantify the impact of increased dietary calcium on bone density during growth and development with possible identification of the characteristics of children most in need of and responsive to this treatment.